TEHRAN (Reuters) - Iranian missiles can reach Israeli nuclear sites and Tehran will respond firmly to any attack, a top commander said on Wednesday.

Israel, like the United States, has not ruled out military action if diplomacy fails to end the row over the Islamic Republic's nuclear plans.

Today, the Islamic Republic of Iran has missiles with the range of 2,000 km (1,250 miles), and based on that all Israeli land including that regime's nuclear facilities are in the range of our missile capabilities, the commander-in-chief of the Revolutionary Guards, Mohammad Ali Jafari, said.

The doctrine of our system is defensive, but in the case of any action by enemies, including the Zionist regime, we will respond firmly using missiles and deter attacks, he said in comments carried by the ISNA news agency.

Iranian officials often refer to Israel's government, which Tehran does not recognize, as the Zionist regime.

Israel, believed to be the only Middle East state with a nuclear arsenal, has described Iran's nuclear ambitions as a threat to its existence.

Israeli and Western officials accuse Iran of seeking to build atomic bombs. Tehran says its nuclear work is aimed at generating electricity not making bombs.

Iran has in the past warned that it would strike Israel and U.S. bases if it was attacked, though Jafari said on Wednesday that neither the United States nor the Israeli military had the ability to strike Iran.

Military analysts say Iranian missiles often draw on technology from North Korea or other countries and also say it is unclear how accurate that Iranian weaponry was.

Defense analyst Paul Beaver said Iran probably had missiles that could reach Israel but he cast doubt on their ability to carry warheads that far and accurately hit long-distance targets.

I would be very surprised if Iran has yet reached that level of sophistication, he said by phone from London. They are moving quickly in that direction but they don't have that capability yet.

(Additional reporting by Fredrik Dahl; Writing by Edmund Blair; Editing by Jon Boyle)